(618349) Williekoorts Mars-crossing Asteroid
Discovered on 25 September 2017 by ATLAS at Haleakala.
Willem P. (“Willie”) Koorts (b. 1958) retired from the South African Astronomical Observatory in 2023. His expertise comprised CCDs, cryostats, general electronics, and mechanics for nearly every telescope on-site. He was instrumental in the construction of the NEO-hunting ATLAS telescope in Sutherland and was dedicated to public outreach in all forms.Naming citation (WGSBN Bull. 3, #3, 17), IAU / Minor Planet Center, via NASA/JPL
Where Williekoorts is today
Seen from above the solar system on 2026-10-14: Williekoorts is 3.04 au from the Sun and 4.02 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 618349 |
| Provisional designation | 2017 SB17 |
| Orbit class | Mars-crossing Asteroid |
| Absolute magnitude (H) | 18.18 |
| Orbital period | 3.53 years |
| Semi-major axis | 2.32 au |
| Perihelion – aphelion | 1.51 – 3.13 au |
| Eccentricity | 0.351 |
| Inclination | 32.4° |
| Closest distance between its orbit and Earth's (MOID) | 0.500 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.